Process and apparatus for evaporating liquids



jufiy w, 1923- 2,4616% E. WmTH-FREY PROCESS AND APPARATUS FOR EVAPORATING LIQUIDS Filed Aug.'l5, 1921 Patented duty 1, 123.

ELIAS WIRTH-FREY, OF AARAU, SWITZERLAND, ASSIGNOR TO THE FIRM AKTIEN- GESELLSCHAFT KUMMLER & MATTER, OF AABAU, SWITZERLAND.

PROCESS AND APPARATUSIOR EVAPORATING LIQUIDS.

Application filed August 15, 1921. Serial No. 492,456.

(GRANTED UNDER THE PROVISIONS OF THE ACT OF MARCH 3, 1921, 41 STAT. L, 1313.)

To all whom it may concern:

Be it known that I, ELIAS WInTH-FREY,

a citizen of the Republic of Switzerland, re-

siding at Laurenzenvorstadt, Aarau, Switzerland, have invented certain new and useful Improvements in Processes and Apparatus for Evaporating Liquids, (for which I have filed applications in Germany, Nov. 11, 1917, application No. 29882; in France,Dec.

to 12, 1918, Patent No. 493794; in Italy, Dec.

16, 1918, Patent No. 80/490; in Germany, Mar. 5, 1918, application No. 30286; in Spain, Jan. -1, 1919, Patent No. 68782; in England, Oct. 20, 1918, Patent No. 123716;

1a in Switzerland, May 8, 1920,, Patent No.-

87745; in Germany, April 13', 1920, application No. 33277; in Switzerland, May 21, a 1920, application No. 5767; in Sweden, June 26, 1920, application No. 3134/; in Nor- June 30, 1920,- application No. 21184/20; in Germany June14, 1920, application No. 33565; in Switzerland, Mar. 31, .1921, application No. 12123; in Italy, April 4, 1921, application No. 301/1430;

andin Canada, June 10. 1921, application No. 255139); and I do hereby declare the following to be a clear, full,- and exact description of the invention, such as will enable others skilled in the art to whichit appertains to make and use the same, reference being had to the accompanying drawings, and to letters or figures of reference marked thereon, which form a part of this specification.

This invention relates to improvements in a process for improving the working of compressors and of evaporating plants and has particular reference" to evaporating plants in which the vapours emanating from the liquid to be evaporatedare used in a compressed condition in ,a closed heating body for heating said liquid. It is 'a wellknown fact that the utilization. of compressed vapours for,'evaporating purposesis only economical if said vapours are compressed to a comparatively low surplus pressure. In such cases, however, the danger exists, that already with small variations in the evaporation the working of the com- 59 pressor becomes unstable'i. e. that a working condition presents itself. in which the output of the compresor has diminished to such an extent that the pressure rise caused evaporation will be completely interrupted.

Although such disturbances might be small during the normal working of an evaporating plant, they may occur in quick succession during short intervals and thus cause a considerable decrease in the specific evap-.

oration figure and thereby in the eiiiciency of the whole plant.

. The object of the present process is to prevent the unfavorable action of such disturbances on the working of the plant. According tothe invention part of the vapours emanating from the liquid and then compressed are' introduced directly into the liquid to be evaporated. In this way a steady and uniform evaporation is promoted and maintained and an interruption of the evaporation is effectively prevented under any working conditions. A working of the evaporating plant that is free of interruptions and is satisfactory as regards efiiciency may in many circumstances only be made possible by the process according "to-the invention.

It has already been known to conduct small quantities of steam into the liquid to v beevaporated. This procedure however, only serves, in lieu of stirring devices or screw conveyors, to impart that strong mechanical motion to the thickened liquid that is necessary for preventing the latter from becoming burnt. v

As the quantity of vapors directly introduoed into the liquid to be evaporated in the form of open jet-sfor the purpose of improving the working of the compressor and of the evaporating plant circulates through the vessel containing the liquid and through the compressor a certain amount of compression work has to be permanently performed in addition to the work for compressing the vapors utilized in the heating body. In order to decrease that additional compressionwork, the-compression of the part of thevapors that is introduced directly into the liquid may according to another feature of the invention, only be efiected to a pressure sufiicient to overcome the'h ydrostatic raeaeeo head in the vessel at the point pf introduction. This means a comparatively important saving in compression work. The vapor directly introduced into the liquid to be adapted to compress the bulkof the vapors utilized for heating purposes.

The accompanying drawing shows by way of example in a diagrammatic manner two arrangements of apparatus for carrying out the process according to the Invention.

Figure 1 is a view partly in section of one form of .apparatus, and

Fig. 2 is a like view of a modification.

1 denotes the vessel containing the liquid to be evaporated. The vapors emanating from the liquid are conducted by a conduit 3 to the suction end of a rotary compressor 4, in which they are compressed and discharged through a conduit 5 to a heating body 2 inside the vessel 1. The compressed vapors deliver their heat to the liquid surroundin bein led off by means of the conduit 6. The eating body 1 is provided with apertures at 9 through which part of the compressed vapors is directly introduced into the liquid to be evaporated in the form of open ets. This arrangement in which the heating body 2 serves at the same time as distributor to the vapors directly introduced into the liquid to be evaporated presents the advantage, that the heating bodyis vented i-nasmuch asqan air collecting inside said body, which air hasafdetrimental effect on the transmission of heat, can escape.

The second constructional example illustrated in Fig. 2 differs .from that shown in Fig. '1 in as much as a special distributor 8 is arranged inside the vessel 1 through 'aper: tures of which the part of the compressed vapors, utilized for improving the working of the compressor and of the evaporatin plant is directly introduced into the liqui n the arrangementshown said vapour is led to the distributor 8-through a conduit 7 which is connected up to a lowervpressure stage of the compressor 4 (i. e. the second pressure stage of a five stage compressor).

the heating body, whereby they are con ensed, the product of condensation In this way the vapors directly introduced into the li uid are only compressed to a pressure su cient to overcome the hydrostatic head present in the vessel 1 above the distributor 8, whereas the greater portion of the vapors utilized for heating purposes is passed through all-the stages of the compressor 4 and com ressed to a higher degree than the vapor le to the distributor 8.

I claim:

1. A process of evaporation. of a liquid, comprising with drawing all the vapors emanating from the liquid to be evaporated, compressmg them, indirectly heating the liquid by means of a portion of such com pressed vapors and liberating a second portion of the compressed vapors within the body of the liquld.

2. A process of evaporation of a liquid, comprising withdrawing all the vapors emanating from the liquid to be evaporated, compressing the greater part of said vapors, indirectly heating the llqllld' by said compressed vapors, compressing a second portion of said first mentioned vapors to a pressure sufiicient to overcome the hydrostatic head in said liquid and freein such second portion of vapor within the ody of said liquid.

3. Apparatus for evaporating liquids, comprising a vessel for containing the liquid to be evaporated, heating means therefor, .means for withdrawing and for compressing the vapors from said vessel and for supplying said. compressed vapors to said heatin means, and means for liberating a portion of the compressed vapors within the'lower part of said vessel.

4. Apparatus for evaporating liquids,

COIIIPIlSlIlg a vessel adapted to contain the liquid to be evaporated, heating means therefor, means for withdrawing and for compressing the'vapors from said vessel and for supplying the greater part of the-compressed vapors to said heating means, means 

